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Epidemiological study of diabetic retinopathy in a primary care setting in Hong Kong
TKW Tam, CM Lau, LCY Tsang, KK Ng, KS Ho, TC Lai
Professional Development and Quality Assurance, Department of Health, 2/F Ngautaukok Jockey Club Clinic, 60 Ting On Street, Hong Kong
OBJECTIVES. To estimate the prevalence and risk
factors of diabetic retinopathy in type 2 diabetic patients, and
to investigate the difference in retinopathy progression in patients
with normal fundi or established retinopathy at baseline and the
risk factors implicated in the progression.
DESIGN. Retrospective community-based study..
SETTING. Ten primary care clinics in Hong Kong.
PATIENTS. Type 2 diabetic patients; subsidiary analysis
included subjects with more than one screening event.
MAIN OUTCOME MEASURES. Patient demographics, baseline
prevalence, and risk factors of diabetic retinopathy; progression
of retinopathy in patients with normal fundi and established retinopathy
at baseline, and the associated risk factors.
RESULTS. A total of 6165 patients were recruited
from January 1998 to May 2004. Primary analysis included 4423 patients
with good-quality retinal photographs. The mean age of the patients
was 60.36 years (standard deviation, 10.80 years; range, 28-94 years),
the mean duration of diabetes was 4.71 years (standard deviation,
4.67 years; range, 0.1-40.6 years), and the mean level of glycated
haemoglobin was 7.47% (standard deviation, 1.44%). The prevalence
of retinopathy at baseline was 28.4%. Subsidiary analysis showed
progression to sight-threatening retinopathy was more common in
the group with baseline retinopathy than that without (7.9% vs 0.7%),
and occurred at a faster rate (mean, 1.5 [range, 0.5-3.0] vs 2.0
[1.0-4.2] years). Logistic regression revealed that the level of
glycated haemoglobin was positively associated with both the onset
(P<0.001) and progression of retinopathy (P=0.03).
CONCLUSION. Optimal glycaemic control is important
for reducing sight-threatening retinopathy. Close observation is
required for patients with established retinopathy as progression
occurs more rapidly.
Hong Kong Med J 2005;11:438-44
Key words: Diabetic retinopathy; Disease progression; Prevalence; Primary health care; Risk factors
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